When trying to update Daylite via Mac App Store, I am being asked to purchase the app again.

Symptom

When attempting to update Daylite via the Mac App Store, the following prompt appears:

"Daylite 4 is already installed and was not purchased from the Mac App Store. Do you want to buy Daylite 4 again?"

Why is this problem occurring

The Mac App Store treats downloading the App as a purchase. While this is free, according to their terminology this considered a purchase.

Solution

There's no requirement to repurchase Daylite 4 as the current version that is installed on your machine is the same one as the Mac App Store. The prompt to "Buy" is actually a prompt to "Update" as the application is a free download. If you would like to proceed and update to the Mac App Store version of Daylite, please follow the steps below:

Quit Daylite 4.

Sign in to the Mac App Store by selecting Store -> Sign In.

Perform a search for Daylite 4.

Click "Install."

Click "Buy."

When the application has downloaded, launch Daylite.

Note:

The official Daylite 4 release and updates are available from the Mac App Store and it is always free. If you get a Beta update, the Mac App store is unaware of this. Because of that, when the Mac App Store checks what version you have, it sees you have the latest version already installed but not from the Store itself. Now you need to update the Store that you have the right version by downloading the update from the Mac App Store. You will not be
charged for the download, as the Daylite application is free.